FFmpeg
vf_photosensitivity.c
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1 /*
2  * Copyright (c) 2019 Vladimir Panteleev
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <float.h>
22 
23 #include "libavutil/imgutils.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/pixdesc.h"
26 #include "avfilter.h"
27 
28 #include "formats.h"
29 #include "internal.h"
30 #include "video.h"
31 
32 #define MAX_FRAMES 240
33 #define GRID_SIZE 8
34 #define NUM_CHANNELS 3
35 
36 typedef struct PhotosensitivityFrame {
37  uint8_t grid[GRID_SIZE][GRID_SIZE][4];
39 
40 typedef struct PhotosensitivityContext {
41  const AVClass *class;
42 
43  int nb_frames;
44  int skip;
46  int bypass;
47 
49 
50  /* Circular buffer */
53 
57 
58 #define OFFSET(x) offsetof(PhotosensitivityContext, x)
59 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
60 
62  { "frames", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
63  { "f", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
64  { "threshold", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
65  { "t", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
66  { "skip", "set pixels to skip when sampling frames", OFFSET(skip), AV_OPT_TYPE_INT, {.i64=1}, 1, 1024, FLAGS },
67  { "bypass", "leave frames unchanged", OFFSET(bypass), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
68  { NULL }
69 };
70 
71 AVFILTER_DEFINE_CLASS(photosensitivity);
72 
74 {
75  static const enum AVPixelFormat pixel_fmts[] = {
79  };
80  return ff_set_common_formats_from_list(ctx, pixel_fmts);
81 }
82 
84 {
87  int skip;
89 
90 #define NUM_CELLS (GRID_SIZE * GRID_SIZE)
91 
92 static int convert_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
93 {
94  int cell, gx, gy, x0, x1, y0, y1, x, y, c, area;
95  int sum[NUM_CHANNELS];
96  const uint8_t *p;
97 
99 
100  const int slice_start = (NUM_CELLS * jobnr) / nb_jobs;
101  const int slice_end = (NUM_CELLS * (jobnr+1)) / nb_jobs;
102 
103  int width = td->in->width, height = td->in->height, linesize = td->in->linesize[0], skip = td->skip;
104  const uint8_t *data = td->in->data[0];
105 
106  for (cell = slice_start; cell < slice_end; cell++) {
107  gx = cell % GRID_SIZE;
108  gy = cell / GRID_SIZE;
109 
110  x0 = width * gx / GRID_SIZE;
111  x1 = width * (gx+1) / GRID_SIZE;
112  y0 = height * gy / GRID_SIZE;
113  y1 = height * (gy+1) / GRID_SIZE;
114 
115  for (c = 0; c < NUM_CHANNELS; c++) {
116  sum[c] = 0;
117  }
118  for (y = y0; y < y1; y += skip) {
119  p = data + y * linesize + x0 * NUM_CHANNELS;
120  for (x = x0; x < x1; x += skip) {
121  //av_log(NULL, AV_LOG_VERBOSE, "%d %d %d : (%d,%d) (%d,%d) -> %d,%d | *%d\n", c, gx, gy, x0, y0, x1, y1, x, y, (int)row);
122  sum[0] += p[0];
123  sum[1] += p[1];
124  sum[2] += p[2];
125  p += NUM_CHANNELS * skip;
126  // TODO: variable size
127  }
128  }
129 
130  area = ((x1 - x0 + skip - 1) / skip) * ((y1 - y0 + skip - 1) / skip);
131  for (c = 0; c < NUM_CHANNELS; c++) {
132  if (area)
133  sum[c] /= area;
134  td->out->grid[gy][gx][c] = sum[c];
135  }
136  }
137  return 0;
138 }
139 
141 {
143  td.in = in;
144  td.out = out;
145  td.skip = skip;
148 }
149 
151 {
154  uint16_t s_mul;
156 
157 static int blend_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
158 {
159  int x, y;
160  uint8_t *t, *s;
161 
163  const uint16_t s_mul = td->s_mul;
164  const uint16_t t_mul = 0x100 - s_mul;
165  const int slice_start = (td->target->height * jobnr) / nb_jobs;
166  const int slice_end = (td->target->height * (jobnr+1)) / nb_jobs;
167  const int linesize = td->target->linesize[0];
168 
169  for (y = slice_start; y < slice_end; y++) {
170  t = td->target->data[0] + y * td->target->linesize[0];
171  s = td->source->data[0] + y * td->source->linesize[0];
172  for (x = 0; x < linesize; x++) {
173  *t = (*t * t_mul + *s * s_mul) >> 8;
174  t++; s++;
175  }
176  }
177  return 0;
178 }
179 
180 static void blend_frame(AVFilterContext *ctx, AVFrame *target, AVFrame *source, float factor)
181 {
183  td.target = target;
184  td.source = source;
185  td.s_mul = (uint16_t)(factor * 0x100);
187  FFMIN(ctx->outputs[0]->h, ff_filter_get_nb_threads(ctx)));
188 }
189 
191 {
192  int badness, x, y, c;
193  badness = 0;
194  for (c = 0; c < NUM_CHANNELS; c++) {
195  for (y = 0; y < GRID_SIZE; y++) {
196  for (x = 0; x < GRID_SIZE; x++) {
197  badness += abs((int)a->grid[y][x][c] - (int)b->grid[y][x][c]);
198  //av_log(NULL, AV_LOG_VERBOSE, "%d - %d -> %d \n", a->grid[y][x], b->grid[y][x], badness);
199  //av_log(NULL, AV_LOG_VERBOSE, "%d -> %d \n", abs((int)a->grid[y][x] - (int)b->grid[y][x]), badness);
200  }
201  }
202  }
203  return badness;
204 }
205 
207 {
208  /* const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format); */
209  AVFilterContext *ctx = inlink->dst;
210  PhotosensitivityContext *s = ctx->priv;
211 
212  s->badness_threshold = (int)(GRID_SIZE * GRID_SIZE * 4 * 256 * s->nb_frames * s->threshold_multiplier / 128);
213 
214  return 0;
215 }
216 
218 {
219  int this_badness, current_badness, fixed_badness, new_badness, i, res;
221  AVFrame *src, *out;
222  int free_in = 0;
223  float factor;
224  AVDictionary **metadata;
225 
226  AVFilterContext *ctx = inlink->dst;
227  AVFilterLink *outlink = ctx->outputs[0];
228  PhotosensitivityContext *s = ctx->priv;
229 
230  /* weighted moving average */
231  current_badness = 0;
232  for (i = 1; i < s->nb_frames; i++)
233  current_badness += i * s->history[(s->history_pos + i) % s->nb_frames];
234  current_badness /= s->nb_frames;
235 
236  convert_frame(ctx, in, &ef, s->skip);
237  this_badness = get_badness(&ef, &s->last_frame_e);
238  new_badness = current_badness + this_badness;
239  av_log(s, AV_LOG_VERBOSE, "badness: %6d -> %6d / %6d (%3d%% - %s)\n",
240  current_badness, new_badness, s->badness_threshold,
241  100 * new_badness / s->badness_threshold, new_badness < s->badness_threshold ? "OK" : "EXCEEDED");
242 
243  fixed_badness = new_badness;
244  if (new_badness < s->badness_threshold || !s->last_frame_av || s->bypass) {
245  factor = 1; /* for metadata */
246  av_frame_free(&s->last_frame_av);
247  s->last_frame_av = src = in;
248  s->last_frame_e = ef;
249  s->history[s->history_pos] = this_badness;
250  } else {
251  factor = (float)(s->badness_threshold - current_badness) / (new_badness - current_badness);
252  if (factor <= 0) {
253  /* just duplicate the frame */
254  s->history[s->history_pos] = 0; /* frame was duplicated, thus, delta is zero */
255  } else {
256  res = av_frame_make_writable(s->last_frame_av);
257  if (res) {
258  av_frame_free(&in);
259  return res;
260  }
261  blend_frame(ctx, s->last_frame_av, in, factor);
262 
263  convert_frame(ctx, s->last_frame_av, &ef, s->skip);
264  this_badness = get_badness(&ef, &s->last_frame_e);
265  fixed_badness = current_badness + this_badness;
266  av_log(s, AV_LOG_VERBOSE, " fixed: %6d -> %6d / %6d (%3d%%) factor=%5.3f\n",
267  current_badness, fixed_badness, s->badness_threshold,
268  100 * new_badness / s->badness_threshold, factor);
269  s->last_frame_e = ef;
270  s->history[s->history_pos] = this_badness;
271  }
272  src = s->last_frame_av;
273  free_in = 1;
274  }
275  s->history_pos = (s->history_pos + 1) % s->nb_frames;
276 
277  out = ff_get_video_buffer(outlink, in->width, in->height);
278  if (!out) {
279  if (free_in == 1)
280  av_frame_free(&in);
281  return AVERROR(ENOMEM);
282  }
284  metadata = &out->metadata;
285  if (metadata) {
286  char value[128];
287 
288  snprintf(value, sizeof(value), "%f", (float)new_badness / s->badness_threshold);
289  av_dict_set(metadata, "lavfi.photosensitivity.badness", value, 0);
290 
291  snprintf(value, sizeof(value), "%f", (float)fixed_badness / s->badness_threshold);
292  av_dict_set(metadata, "lavfi.photosensitivity.fixed-badness", value, 0);
293 
294  snprintf(value, sizeof(value), "%f", (float)this_badness / s->badness_threshold);
295  av_dict_set(metadata, "lavfi.photosensitivity.frame-badness", value, 0);
296 
297  snprintf(value, sizeof(value), "%f", factor);
298  av_dict_set(metadata, "lavfi.photosensitivity.factor", value, 0);
299  }
301  if (free_in == 1)
302  av_frame_free(&in);
303  return ff_filter_frame(outlink, out);
304 }
305 
307 {
308  PhotosensitivityContext *s = ctx->priv;
309 
310  av_frame_free(&s->last_frame_av);
311 }
312 
313 static const AVFilterPad inputs[] = {
314  {
315  .name = "default",
316  .type = AVMEDIA_TYPE_VIDEO,
317  .filter_frame = filter_frame,
318  .config_props = config_input,
319  },
320 };
321 
322 static const AVFilterPad outputs[] = {
323  {
324  .name = "default",
325  .type = AVMEDIA_TYPE_VIDEO,
326  },
327 };
328 
330  .name = "photosensitivity",
331  .description = NULL_IF_CONFIG_SMALL("Filter out photosensitive epilepsy seizure-inducing flashes."),
332  .priv_size = sizeof(PhotosensitivityContext),
333  .priv_class = &photosensitivity_class,
334  .uninit = uninit,
338 };
ff_get_video_buffer
AVFrame * ff_get_video_buffer(AVFilterLink *link, int w, int h)
Request a picture buffer with a specific set of permissions.
Definition: video.c:98
td
#define td
Definition: regdef.h:70
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(photosensitivity)
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
config_input
static int config_input(AVFilterLink *inlink)
Definition: vf_photosensitivity.c:206
out
FILE * out
Definition: movenc.c:54
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1019
PhotosensitivityContext
Definition: vf_photosensitivity.c:40
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
PhotosensitivityContext::history
int history[MAX_FRAMES]
Definition: vf_photosensitivity.c:51
PhotosensitivityContext::badness_threshold
int badness_threshold
Definition: vf_photosensitivity.c:48
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
av_frame_make_writable
int av_frame_make_writable(AVFrame *frame)
Ensure that the frame data is writable, avoiding data copy if possible.
Definition: frame.c:490
pixdesc.h
AVFrame::width
int width
Definition: frame.h:361
GRID_SIZE
#define GRID_SIZE
Definition: vf_photosensitivity.c:33
AVOption
AVOption.
Definition: opt.h:247
b
#define b
Definition: input.c:40
data
const char data[16]
Definition: mxf.c:143
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: vf_photosensitivity.c:73
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:196
float.h
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
AVDictionary
Definition: dict.c:30
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:153
video.h
convert_frame_partial
static int convert_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Definition: vf_photosensitivity.c:92
formats.h
ThreadData_blend_frame::target
AVFrame * target
Definition: vf_photosensitivity.c:152
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: vf_photosensitivity.c:306
photosensitivity_options
static const AVOption photosensitivity_options[]
Definition: vf_photosensitivity.c:61
PhotosensitivityContext::last_frame_e
PhotosensitivityFrame last_frame_e
Definition: vf_photosensitivity.c:54
PhotosensitivityContext::last_frame_av
AVFrame * last_frame_av
Definition: vf_photosensitivity.c:55
ThreadData_convert_frame::skip
int skip
Definition: vf_photosensitivity.c:87
ff_vf_photosensitivity
const AVFilter ff_vf_photosensitivity
Definition: vf_photosensitivity.c:329
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:50
av_cold
#define av_cold
Definition: attributes.h:90
width
#define width
s
#define s(width, name)
Definition: cbs_vp9.c:257
ThreadData_convert_frame
Definition: vf_photosensitivity.c:83
slice_end
static int slice_end(AVCodecContext *avctx, AVFrame *pict)
Handle slice ends.
Definition: mpeg12dec.c:2041
PhotosensitivityFrame::grid
uint8_t grid[GRID_SIZE][GRID_SIZE][4]
Definition: vf_photosensitivity.c:37
ff_set_common_formats_from_list
int ff_set_common_formats_from_list(AVFilterContext *ctx, const int *fmts)
Equivalent to ff_set_common_formats(ctx, ff_make_format_list(fmts))
Definition: formats.c:703
OFFSET
#define OFFSET(x)
Definition: vf_photosensitivity.c:58
outputs
static const AVFilterPad outputs[]
Definition: vf_photosensitivity.c:322
ctx
AVFormatContext * ctx
Definition: movenc.c:48
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:152
convert_frame
static void convert_frame(AVFilterContext *ctx, AVFrame *in, PhotosensitivityFrame *out, int skip)
Definition: vf_photosensitivity.c:140
arg
const char * arg
Definition: jacosubdec.c:67
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
av_frame_copy_props
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:537
FLAGS
#define FLAGS
Definition: vf_photosensitivity.c:59
ThreadData_convert_frame::out
PhotosensitivityFrame * out
Definition: vf_photosensitivity.c:86
src
#define src
Definition: vp8dsp.c:255
PhotosensitivityFrame
Definition: vf_photosensitivity.c:36
abs
#define abs(x)
Definition: cuda_runtime.h:35
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
PhotosensitivityContext::history_pos
int history_pos
Definition: vf_photosensitivity.c:52
source
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a source
Definition: filter_design.txt:255
AV_PIX_FMT_RGB24
@ AV_PIX_FMT_RGB24
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:68
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_frame_copy
int av_frame_copy(AVFrame *dst, const AVFrame *src)
Copy the frame data from src to dst.
Definition: frame.c:678
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: vf_photosensitivity.c:217
blend_frame
static void blend_frame(AVFilterContext *ctx, AVFrame *target, AVFrame *source, float factor)
Definition: vf_photosensitivity.c:180
height
#define height
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
internal.h
AV_OPT_TYPE_FLOAT
@ AV_OPT_TYPE_FLOAT
Definition: opt.h:227
PhotosensitivityContext::skip
int skip
Definition: vf_photosensitivity.c:44
i
int i
Definition: input.c:406
NUM_CHANNELS
#define NUM_CHANNELS
Definition: vf_photosensitivity.c:34
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:804
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
ThreadData_blend_frame::s_mul
uint16_t s_mul
Definition: vf_photosensitivity.c:154
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:56
PhotosensitivityContext::bypass
int bypass
Definition: vf_photosensitivity.c:46
AVFilter
Filter definition.
Definition: avfilter.h:149
ThreadData_blend_frame
Definition: vf_photosensitivity.c:150
ThreadData_blend_frame::source
AVFrame * source
Definition: vf_photosensitivity.c:153
MAX_FRAMES
#define MAX_FRAMES
Definition: vf_photosensitivity.c:32
AVFrame::height
int height
Definition: frame.h:361
blend_frame_partial
static int blend_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Definition: vf_photosensitivity.c:157
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:224
avfilter.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:346
factor
static const int factor[16]
Definition: vf_pp7.c:76
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
inputs
static const AVFilterPad inputs[]
Definition: vf_photosensitivity.c:313
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:241
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:153
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
imgutils.h
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
PhotosensitivityContext::nb_frames
int nb_frames
Definition: vf_photosensitivity.c:43
get_badness
static int get_badness(PhotosensitivityFrame *a, PhotosensitivityFrame *b)
Definition: vf_photosensitivity.c:190
ff_filter_execute
static av_always_inline int ff_filter_execute(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
Definition: internal.h:143
NUM_CELLS
#define NUM_CELLS
Definition: vf_photosensitivity.c:90
int
int
Definition: ffmpeg_filter.c:156
snprintf
#define snprintf
Definition: snprintf.h:34
PhotosensitivityContext::threshold_multiplier
float threshold_multiplier
Definition: vf_photosensitivity.c:45
ThreadData_convert_frame::in
AVFrame * in
Definition: vf_photosensitivity.c:85